The present invention relates to a semiconductor device, particularly, a technology effective when applied to, for example, a resin-sealing type semiconductor device using a metal member.
Semiconductor devices used in the automotive field and the like are used under a severe usage environment so that they are required to have much higher reliability compared with those for consumer use or industrial use. In resin-sealing type semiconductor devices using a metal member, peeling of the sealing resin from the metal member (metal lead or the like) occurs due to moisture absorption of the resin and thermal stress in the sealing body (package). This peeling becomes a cause for generation of cracks at the joint between a semiconductor element and the metal member, leading to formation of defective semiconductor devices.
As a conventional method for firmly bonding a metal member and a sealing resin, a method of roughening the surface of the metal member by plating or etching is known.
For example, Japanese Patent Laid-Open No. 148508/1997 (Patent Document 1) discloses as follows relating to a resin-sealing type semiconductor device. A needle-like or dendritic roughened layer is formed by electroplating a Cu-based or Fe-based leadframe with Cu, CuNi, Zn, Ni, or the like at a current density exceeding the critical current density. A covering layer is then formed on the resulting roughened layer by electroplating it with two Cu and Zn layers, CuZn, Cr, ZnCr, two Ni and InZn layers, NiP, or two Ni and CuZn layers at a current density not greater than the critical current density. The roughened layer and the covering layer cooperatively contribute to improvement in bond strength between the leadframe and the resin and improvement in reliability such as moisture resistance, thermal shock resistance, or the like.
Japanese Patent Laid-Open No. 2002-299538 (Patent Document 2) discloses as follows relating to a leadframe and a semiconductor package using it. The surface of the leadframe to be brought into contact with a sealing resin is subjected to roughening plating, followed by plating, with a metal, a portion on the plated leadframe and necessary for wire bonding.
Japanese Patent Laid-Open No. 46116/1996 (Patent Document 3) discloses as follows relating to a leadframe. Either one of the following methods is used for forming a roughened surface on at least a portion of the surface of the leadframe to be molded. One of them is etching Cu or Ar in an aqueous solution containing a water soluble reducing agent such as ferric chloride or hydrazine. The other one is electrolytic etching with a nitrate-based electrolyte under treatment conditions of a voltage of 10V or greater but not greater than 50V and an anode current density of 40 A/dm2 or greater but not greater than 200 A/dm2. Formation of such a roughened surface improves adhesion between the leadframe and the molding resin.    Patent Document 1: Japanese Patent Laid-Open No. 148508/1997    Patent Document 2: Japanese Patent Laid-Open No. 2002-299538    Patent Document 3: Japanese Patent Laid-Open No. 46116/1996